1. Field of the Invention
This invention relates to improvements in a memory device for storing data such as a number of film frames.
2. Description of the Related Art
Recently, in the field of cameras, as the application of electronics advances, an increasing number of means for memorizing the number of film frames and other various data to be used in control, counting, or display are taking an electrical form. Such an electrical memory means should have a storage medium capable of electrical writing and erasing. In this respect, use may be made of a solid state non-volatile memory element, such as an EEPROM (electrically writable and erasable programmable read only memory). Since, without the necessity of a backup battery for the electrical power source, an EEPROM retains the memory contents, it can be said that there is a very advantageous prospect. Whilst it does not suffer losing the once stored data, the EEPROM has, however, generally a rewrite life-time of about ten thousand maximum permissible number cycles, which is shorter than a RAM. Therefore, if the number of executed cycles of writing and erasing are unevenly concentrated in a particular portion of the storage area, it will not withstand a long-pending usage. Hence, a novel implementation of the EEPROM in order for it to be applied to the above-described purpose had to be made.